A monopole antenna is half of a dipole, operated in conjunction with its image in a conducting ground plane perpendicular to the dipole. Monopoles are often useful as vehicle antennas where the ground plane is the surface of the vehicle. A monopole may be formed in a variety of sizes and shapes, depending on a particular application.
Monopole antennas are intrinsically narrow band, and the development of a broadband monopole that will operate across a wide frequency band presents a design challenge. Producing a broadband monopole that will achieve relatively uniform omnidirectional gain with input impedance matched across the entire bandwidth presents an even greater design challenge.
An additional hurdle is presented when the broadband monopole is sought to be used on an aircraft, particularly including a relatively small aircraft. Such a design must not only accomplish broadband, omnidirectional gain, and impedance matching, but must not degrade aerodynamic performance. Accordingly, there is a need for an improved broadband monopole antenna suitable for use on small aircraft.